In garment pattern warehousing and like operations, it is customary to organize compartments, each containing a stack of envelopes containing patterns of singular character, in access position to pattern retrieval apparatus. Such retrieval apparatus may be supported for selective horizontal and vertical movement to face a preselected single compartment, as shown in Castaldi U.S. Pat. No. 3,690,479, or may comprise a unit movable horizontally and having plural retriever devices arranged vertically so as to face plural vertically stacked compartments, as shown in Dennis U.S. Pat. No. 3,076,566.
As is disclosed in the two above-referenced patents, retriever devices for garment patterns involve an air pressurized suction head selectively translatable into engagement with the lead article in a compartment and adapted to move the engaged article exteriorly of the stack on suction head withdrawal. In the first-referenced patent, the stack of patterns is biased against detent rods which are disposed in the access opening of the compartment and engage frontal marginal portions of the lead pattern to restrain the same from movement exteriorly of the compartment. On withdrawal from the stack, such lead pattern is engaged centrally by the suction head and the pattern central portion is withdrawn, while bowed relative to the pattern marginal portions, until the pattern edges are moved clear of the restraining detent rods. In the second-referenced patent, similar lead pattern bowing or deflection occurs to permit the pattern to free itself of peripheral compartment lips serving likewise to retain patterns in their stacks.
Deflection of retrieved articles such as occurs in each of the referenced pattern retrieving systems is undesirable as giving rise to possible damage to envelope contents. Further, the envelope-contained patterns in different compartments are typically diverse from one another in respect of numbers of sheets and types of sheets, i.e., tissue versus relatively rigid sheets. Thus, where either a common pattern retriever device is used for retrieval from all bins or where plural pattern retrievers of like structure are employed, retriever suction level need be set to accommodate the pattern having greatest resistance to deflection. At the same time, use of said high suction level with, for example, a pattern comprising but a single tissue is not only a wasteful endeavor but is more likely to damage the retrieved pattern.
In article retrieval systems known to applicant other than those particularly involving the retrieval of garment patterns, like article deflection is also seen to occur. In Bliss U.S. Pat. No. 3,322,301 the lead article edges are disposed in engagement with restraint elements aside the article stack. A suction head is moved into engagement with the lead article and applies suction to its marginal portions to deflect them outwardly of the stack with the article center remaining in engagement with the stack. In Seragnoli U.S. Pat. No. 3,816,760 a suction head comprised of laterally displaced suction tubes is moved into engagement with the lead article whereupon the spacing between the tubular elements is reduced with consequent bowing deflection of the article central portion relative to the article edges as in the above-referenced pattern retrieval patents.